package com.learn.designpattern.singleton.type3;

public class SingletonTest03 {

    public static void main(String[] args) {
        Singleton instance=Singleton.getInstance();
        Singleton instance2=Singleton.getInstance();
        System.out.println(instance==instance2);
        System.out.println("instance.hashCode=" + instance.hashCode());
        System.out.println("instance2.hashCode=" + instance2.hashCode());
    }
}

class Singleton{

    private static Singleton instance;

    private Singleton(){}

    //提供一个静态的公有方法，当使用到该方法时，才去创建 instance
    //即懒汉式
    public static Singleton getInstance(){
        if(instance==null){
            instance=new Singleton();
        }

        return instance;
    }
}